This invention relates to impact-resistant material systems.
There are numerous types of armor and armor systems for use in protecting people and equipment from metal fragments, bullets, and other projectiles of various types. Conventional armor is thick steel plate that is formulated and manufactured to have great strength and toughness. It has been necessary to increase the thickness of armor plate in response to advances in projectile technology, but there are limits to the amount of weight due to armor that military equipment, such as tanks. ships, and airplanes, can carry and still be militarily effective. And, of course, personnel armor using any significant amount of steel is not practical.
Numerous types of armor and armor systems that utilize ceramics, polymers, and combinations thereof have been developed. The following patents teach armor which does not rely on steel plate to stop projectiles.
Leo J. Windecker, "Impact Resistant Composite Structure, " U.S. Pat. No. 4,232,069, November 1980. This patent teaches an impact-resistant composite structure comprised of a base portion of several plies of high tensile strength fiber sheets impregnated with an adhesive elastic resin. This flexible base portion of the structure has mounted on it a facing portion (facing an incoming projectile) consisting of a plurality of closely spaced ceramic tiles in a thick layer of an adhesive elastic resin in which microspheres are dispersed. The thickness of the adhesive elastic layer is preferably three times the thickness of the ceramic tiles. The purpose of the microspheres in the adhesive is to isolate the ceramic tiles from each other so that a bullet hitting one tile does not damage adjoining tiles. In another embodiment, the ceramic tiles are covered with several plies of high tensile strength fiber sheets impregnated with an adhesive elastic resin, this portion of the structure being identical to the base portion.
Robert E. J. Poole, Jr., "Novel Compositions," U.S. Pat. No. 4,061,815, December 1977. This patent teaches laminated structures comprised of an outer projectile-receiving layer which is preferably aluminum armor plate, an inner layer of noncellular polyurethane, and an inner skin fabricated from any suitable material, such as aluminum sheet or polyester. In one embodiment a particulate filler, such as gravel, crushed granite, or ceramics, is embedded in the polyurethane layer. Several filled polyurethane layers may be utilized. The polyurethane layer may also contain within it one or more layers of corrugated spring steel strips.
Hugh C. Gardner et al., "Impact Resistant Matrix Resins for Advanced Composites," U.S. Pat. No. 4,661,559, April 1987. This patent teaches composite armors consisting of diamine hardeners, epoxy resins, and thermoplastic polymers.
Carol W. Clausen, "Armor Comprising a Plurality of Loosely Related Sheets in Association with a Frontal Sheet Comprising Metal Abrading Particles." U.S. Pat. No. 4,292,882, October 1981, This patent teaches a flexible light armor comprised of multiple layers, where one layer is comprised of a hard particulate material, such as alumina, in a binder material. In a preferred embodiment, two or more layers of flexible fabric are impregnated with an abrasive material and bonded together with a soft and flexible latex cement.
Richard L. Cook et al., "Ballistic Armor System," U.S. Pat. No. 4,179,979, December 1979. This patent teaches armor consisting of layers of ceramic spheres with a material in sheet form interlaced among the spheres and an adhesive binder filling the voids between the spheres.
Richard J. Cook, "Hard Faced Ceramic and Plastic Armor," U.S. Pat. 3,509,833, May 1970. This patent teaches a ceramic and plastic armor system. Alumina tiles are bonded to a substrate by a flexible bonding agent. The substrate may be layers of resin-impregnated glass fabric or a homogeneous tough plastic material. The tiles are then covered with a flexible material such as ballistic nylon or resin-impregnated glass fabric.